Asked about Aubameyang, who has been linked with a winter exit from the Westfalenstadion, Bosz told his prematch news conference: "He is an awful player, very bad ... it's a joke.

"I hope he does not go to Madrid. He has the quality to play for them, but I hope he stays with us."

Bosz will be looking to Aubameyang to inspire his struggling Dortmund side at the Bernabeu on Wednesday.

BVB have already been eliminated from the Champions League after earning just two points in the group so far, and they would exit Europe entirely if Apoel Nicosia, who face Tottenham, better their result against Madrid.

"Reaching the Europa League is an obligation for me," former Ajax boss Bosz, who was given a vote of confidence by CEO Hans-Joachim Watzke on Tuesday, said.

"We'll try to put in a good performance. That's important for our self-confidence. And if possible, we want to come away with one or even all three points."

Pierre-Emerick Aubameyang has been linked with a winter transfer, with AC Milan and Real Madrid suggested as destinations.

Having started the domestic season with 19 points from just seven games, Dortmund have collapsed, picking up only three draws from the next seven Bundesliga matches. They have dropped from first to sixth in the standings.

Since beating Augsburg 2-1 on Sept. 30, Dortmund have won just one of the 12 matches in all competitions that followed, drawing five and losing six. Their sole win came in a 5-0 cup win at third-league side FC Magdeburg.

Madrid, too, have had a disappointing start to the season, but Bosz laughed off reporters' enquiries as to whether he deems Zidane's side to be in crisis, saying: "If they are in a crisis, where are we?"

Stephan Uersfeld is the Germany correspondent for ESPN FC. Follow him on Twitter @uersfeld.